CHATHAM, Va. -- Underneath a plot of farmland used to raise cattle, hay and timber in south central Virginia lies what is thought to be the largest deposit of uranium in the United States.

Now, three decades after the deposit was found, landowner Walter Coles has set his sights on mining the 200-acre site despite concerns of environmental groups and residents about unearthed radioactive material that could contaminate the area's land, air and source of drinking water.

As the United States searches for alternative energy sources, Virginia has a geological discovery in its back yard that could drastically change the nation's reliance on foreign oil. The estimated 110 million pounds of uranium in Pittsylvania County, worth almost $10 billion, could supply all of the country's nuclear power plants for about two years.

There's a hurdle to clear before an ounce of the element can be mined: It's illegal to dig for the stuff in Virginia. But the General Assembly is considering changing that.

Coles, 69, who recently retired from the federal government and moved from the Washington area back to the family farm, said mining companies have been offering to buy his land. Instead of taking the money, he decided to stay. He said he wanted to make sure that the mining was done safely and that it would benefit the community through jobs, taxes and economic development.

"There's too much uranium here. Somebody's going to mine it," Coles said. "I felt like while I was alive, it was my duty to make sure it was done right."

This month, Coles's company, Virginia Uranium, will try to persuade the General Assembly to take the first step -- approving a $1 million study that will explore whether uranium can be safely mined in Virginia. If the study shows that it can be done, the company will ask the legislature to lift a state ban on uranium mining.

The issue is dividing lawmakers, who will begin their 60-day session Jan. 9, but company officials have reasons to be optimistic.

Gov. Timothy M. Kaine (D) supports a study, and a state energy report released this fall recommends one. Coles's brother-in-law, Whitt Clement, who served as a legislator and as state transportation secretary, is heading what is expected to be a strong lobbying effort. Henry Hurt, an investor and a childhood friend of Coles's, has a son Robert, a Pittsylvania delegate who won a state Senate seat in November.

Virginia banned uranium mining in 1982, but Coles's company recently got a state permit to drill 40 holes to examine the material.

A growing coalition of environmental groups and concerned residents, some of the same residents who helped institute the ban 30 years ago, have started spreading the word about their opposition and are planning to travel to Richmond to fight Coles.

Elizabeth Haskell, a former state secretary of natural resources who served on a board that studied uranium mining in the early 1980s, said Coles is thinking about money, not safety. "He has got dollar signs in his eyes," she said.